Previous studies carried out on environmental contamination int he Massena area of the St. Lawrence River have focused on hazardous wastes from the General Motors Corporation plant near Massena. However, there are two aluminum manufacturing plants in the area and discharges from these facilities have released pollutants to the river. The major objective of this proposal is to determine the aquatic bioavailability of polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs) and polychlorinated dibenzo-p-dioxins (PCDD)s/polychlorinated dibenzofurans (PCDFs) from sediments collected near discharge points from each plant. This task will be accomplished by exposing the midge larva, Chironomus tentans, and caged-carp to sediments in the laboratory and in the field respectively. In addition carp and preflight juveniles from two species of dabbling ducks (gadwalls and mallards) will be collected in the vicinity of each plant site and at a control site. Using a state-of-the-art gas chromatograph (GC)/high resolution mass spectrometer (MS), it should be possible to detect 1 picogram (pg) amounts of individual compounds in extracts from samples (fat, liver, larvae, insects and sediments). The secondary objective of the proposed research project will be to determine the influence of metabolism on selective retention of the pollutants. Generally biota accumulate only toxic 2,3,7,8-substituted PCDDs and also, in the case of PCDFs, small quantities of non-2,3,7,8- substituted isomers. However many of the Massena area fish and wildlife samples were found to contain higher quantities of non-2,3,7,8-substituted PCDFs than 2,3,7,8-substituted isomers. To test the hypothesis that metabolism influences the retention of PCDDs/PCDFs and related compounds the activity of hepatic Cytochrome P450 enzymes in the carp and duck samples will be determined using the aryl hydrocarbon hydroxylase (AHH) assay. Results from this study should provide for a better understanding of the relative contributions of individual industries to pollution of fish and wildlife consumed by residents of the Massena area.